Heat treating induction coil



Aug. 23, 1966 T. G. EANNARINO 3,268,218

HEAT TREATING INDUCTION COIL Filed Sept. 10, 1965 2 Sheets-Sheet l Wyn 7m A 43 46 0 52 e0 52 41 eo 1 I I l\ i INVENTOR THOMAS G. EANNARINO ATTORNEY g- 23, 1955 T. G. EANNARINO 3,268,218

HEAT TREATING INDUCTION COIL Filed Sept. 10, 1963 2 Sheets-Sheet 2 United States Patent 3,268,218 HEAT TREATING INDUCTION COIL Thomas G. Eannariuo, Park Ridge, Ill., assignor to Teletype Corporation, Skolrie, Ill., a corporation of Delaware Filed Sept. 10, 1963, Ser. No. 308,027 Claims. (Cl. 266-6) This invention relates to heat treating methods and apparatus and more particularly to a method of and apparatus for induction heating parts and for rapidly quenching or chilling the parts to impart hardness to them.

In the heat treating of metallic parts to impart hardness to them, strains are frequently introduced into the part in the heating of it which upon the sudden cooling of the part cause it to become distorted thereby necessitating a straightening operation. This is particularly true when parts are of rather thin cross section. Furthermore, when such parts are heated by an induction heating coil, a problem is posed, particularly with parts of relatively small cross section, in quenching the part with sufficient rapidity to prevent partial annealment of it.

In the past, parts have been induction heated and then discharged from the heating coil into a quenching bath. This process is not highly satisfactory since the parts in moving from the heating coil to the quenching bath may be bent slightly while moving from the coil to the bath due to the fact that they are pliable when they are at a temperature high enough to serve the intended purpose.

It is an object of the present invention to provide a simple, highly efficient heat treatingapparatus.

Another object of the invention is to provide a heat treating apparatus which will prevent the introduction of distortion in the part during the quenching or chilling of it.

A further object of the invention is to provide a simple and inexpensive method of heat treating metal parts.

In accordance with one embodiment of the invention a single turn induction coil is provided which is comprised of three parts, two of which comprise upper and lower halves of the coil and the third of which comprises a shunt for interconnecting the ends of the two halves to form a complete single turn coil. Suitable bus bars are provided for engagement with the two coil halves or members to serve as spacing elements for cooperation with the shunt member to properly space the coil halves with respect to a part supported in spaced relation to the coil halves and in a position between them. The coil halves are movable relative one to another and to the bus bars so that they may be engaged with the bus bar and then shunted by the shunt member to complete the formation of the single turn coil. The retraction of the shunt member from engagement with the two coil halves and the disengagement of the coil halves from the .bus bars will permit the two coil halves to be moved together so that the part which has been heated between the coil halves by induced current may be chilled by the coil halves through which a coolant is constantly circulated.

A complete understanding of the invention may be had by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of an apparatus made in accordance with the present invention;

FIG. 2 is a view in perspective of a set of coil halves and a shunt member shown in operative relation to a pair of current feeding bus bars;

FIG. 3 is a side elevational view of a coil with a part to be treated positioned between the halves of the coil;

FIG. 4 is a plan view of the lower half of the coil 3,268,218 Patented August 23, 1966 ice with a part positioned thereon shown in dot and dash lines;

FIG. 5 is a fragmentary cross sectional view taken substantially along the line 55 of FIG. 4 in the direction of the arrows showing details of the mounting of the support for the part to be heat treated; and

FIG. 6 is a fragmentary perspective view of another type of support for a part to be heat treated.

Referring now to the drawings wherein like reference numerals designate the same parts throughout the several views, particular reference being had to FIG. 1, it will be seen that an apparatus is provided comprising a turntable 10 which may be indexed step-by-step to present a pair of induction coil components or coil halves 11 and 12 into association with a third induction coil component or shunt member 13 and a pair of bus bars 14 and 15 and then to move the coil halves out of association with the shunt member 13 and bus bars 14 and 15. The bus bars 14 and 15 are spaced apart by a suitable insulator 16 and may be fed with high frequency current from any suitable source (not shown). The pair of bus bars 14 and 15 are radially aligned with the shunt member 13 at one station of the turntable 10.

The coil halves 11 and 12 are each made up of a pair of plate members 17 and 18, and 19 and 20, respectively, suitably brazed together and having coolant passages 21 and 22, respectively, formed through them. The coolant passage 21 extends longitudinally adjacent to one side of the plate member 17 and then upwardly to communicate with a continuation thereof in plate member 18 and thence across the plate member 18 and longitudinally of the plate members 18 and 17 in a manner the reverse of the other course of the passage 21. The passage 22 through the plate members 19 and 20 is the opposite of that in the members 17 and 18. The shunt members 13 have coolant passages 23. extending through them. Coolant may be pumped, in the direction shown by the arrows 24, 25 and 26, through the plate members and shunt members. The arrows represent flexible hose connections made of a nonconducting material. The coil halves 12 are mounted on suitable insulators 30 on the turntable 10 and the coil halves 11 are suspended on piston rods 31 by insulator members 32. Each piston rod 31 cooperates with a cylinder 33 individual to the coil half 11 for imparting reciprocation to the coil half 11 to clamp it into tight engagement with bus bar 14 and also to insure good electrical contact between the plate member 20 of coil half 12. The cylinder 33 may be supplied with fiuid to move the piston rod 31 from the position shown in FIG. 2 in solid lines to the position shown in dotted lines to permit a part to be heat-treated to be mounted between the coil halves 11 and 12. The shunt members 13 are each mounted on suitable insulators 34 that are slidable in ways 35 formed in the turntable 10. When the turntable 10 is indexed it will carry one set of coil halves 11 and 12 and their associated shunt member 13 into position between the bus bars 14 and 15 and an insulator member 36 mounted on the end of a piston rod 37 which may be reciprocated upon the admission of fluid under pressure to a cylinder 38.

The coil halves 11 and 12 have their left ends (FIGS. 2 and 3), oppositely tapered as shown at 42 and 43, respectively, for cooperation with beveled surfaces 44 and 45 formed on the shunt member 13 whereby when the piston rod 31 is actuated to clamp the coil halves 11 and 12 into electrically conductive engagement with the bus bars 14 and 15 and the piston rod 37 is actuated to move the shunt member 13 to the right, the tapered portions 42 and 43 of the coil halves '11 and 12 and the spacing of the bus bars 14 and 15 will cause the upper coil half 11 and lower coil half 12 to be aligned and spaced a predetermined distance one from another in substantial parallelism. The plate member 19 of the lower coil half 12 has a pair of support members 46 and 47 mounted in it for resiliently supporting a part 48 in spaced relation to the lower coil half 12. The support members 46 and 47 may be of any suitable construction and in the example illustrated in FIGS. 4 andS, are comprised of a cylindrical member 46 having a slot 49 formed in it. The member 46 is normally urged upwardly to the position shown in FIGS. 3 and 5 by a compression spring 50seated in a socket 51 in the insulator 30. The support member 46 is made of a nonconducting material and a pin 52 extending through the slot 49 regulates the amount that the spring 50 can raise the support member 46 with respect to plate member 19.

In the embodiment shown in FIG. 6 a support member 55 is shown which is generally of T shaped configuration and has a slot 56 formed in it for cooperation with a pin similar to the pin 52. This support member 55- is shown removed from the coil half 12 more clearly to illustrate it but is designed to move into a slot 57 in the coil half 12 and to support a part on its upper tapered edge 58.

In the operation of the apparatus the upper coil half 11 may be moved to the position shown in dot and dash lines in FIG. 2 and a part 48 may be placed upon the support members 46 and 47. Thereafter, the table may be indexed to carry the coil halves -11 and 12, with which a part to be heat treated has been associated, into position between the piston rod 37 and-bus bars 14 and 15. After the coil halves 11 and 12 and shunt member 13 have thus been aligned between the piston 37 and bus bars 14 and 15, the piston rod 31 may be moved downwardly to clamp the plate members 18 and 20 into good conducting engagement with the bus bars 14 and 15 and thereupon the piston rod 37 may be actuated to move the shunt member 13 into tight engagement with the coil halves 1 1 and 12. Due to the large flat surfaces of the members 18 and 20 and the bus bars 14 and 15 a good electrical conducting connection will be made between the bus bars 14 and 15 and the surfaces of members 18 and 20 and due to the tapered configuration of the left ends of the plates 17 and 19 of coil halves 11 and 12 and the beveled surfaces 44 and 45 of the shunt member 13 a good electrical conducting connection will be made between the shunt member and coil halves thereby to complete the single turn induction coil.

With a part 48 thus positioned within the single turn induction coil, current may be supplied to the bus bars 14 and 15 to induce a heating current in the part 48. As soon as the induced current in the part 48 has raised the part to the desired temperature, the piston rod 31 may be moved upward slightly and the piston rod 37 may be moved leftward sufficiently to release the shunt member 13 from the coil halves 11 and 12 and the table may be indexed one step. After this indexing of the table the piston rod 31 may be actuated to move the coilhalves 11 and 12 toward each other to compress thesprings 50 and clamp the part 48 between the flat bottom surface of the plate 17 of coil half 11 and the flat upper surface of the plate 19 of coil half 12 thereby to chill the part since coolant is continuously being circulated through the plate members 17 and 19 which comprise the cooling surfaces. With this particular type of structure the coil halves 11 and 12 will serve to chill the part quickly while holding it against warping or other distortion. The plate members 17 and 19 may be held in clamping engagement with the part 48 until it is properly chilled or quenched and then the piston 31 may be actuated to retract the coil half 11 to its uppermost position as shown in dotted lines in FIG. 2 whereupon the heat treated part may be removed and another part placed in position to be heat treated.

Some parts, such as the part 48 illustrated in FIGS. 3 and 4, may either distort slightly in a lateral direction bent slightly and since it is possible that the angularity of one leg of the part 48 with respect to the other leg may be critical, the lower die may be provided with pins 60 that have conical tips so that as the part 48, after having been heated, may be re-formed to its proper shape as it is clamped between the plates 17 and 19. When the plates 17 and 19 are clamped together, these pins 60 which are fixed to plate 19, will enter suitable indentations 61 formed in the plate 17. The location of the pins 60 as shown in FIG. 4 is simply for purposes of illustration and the pins could be placed at any desired location so that the part in its heated and semi-plastic condition may readily be restored to its proper form.

Although only one embodiment of the invention is shown in the drawings and described in the foregoing specification it will be understood that invention is not limited to the specific embodiment described but is capable of modification and rearrangement and substitution of parts and elements without departing from the spirit of the invention.

What is claimed is:

1. In a heat treating apparatus,

(a) a pair of bus bars spaced one from the other for supplying high frequency current to the apparatus,

(b) a first induction coil component of conducting material engageable with one of said bus bars,

(0) a second induction coil component of conducting material engageable with the other of said bus bars,

(d) a shunt member of conducting material engageable with said first and second induction coil components to form a single turn induction coil,

(e) means for supplying coolant to the interior of said induction coil components and shunt member,

(f) means resiliently mounted on said first induction coil component for supporting a part to be heat treated in spaced relation to said first and second induction coil components when they are in engagement with the bus bars and with said shunt member,

(g) means for moving said first and second induction coil components into and out of a communicating position with respect to said pair of bus bars, and

(h) means for actuating said induction coil components when they are out of said communicating position with respect to said pair of bus bars to compress said resiliently mounted supporting means, thereby causing intimate clamping engagement of said first and said second induction coil components with said part to chill it by conduction.

2. An apparatus according to claim 1 wherein the means for actuating the first and second induction coil components is operative to move said means for supporting the part to a position flush with a surface of the first induction coil component when said induction coil components are out of said communicating position with respect to said bus bars and also operative to clampingly engage the first and second components with their respective bus bars when said induction coil components are in said communicative position with respect to said bus bars.

3. In a heat treating apparatus,

(a) a pair of bus bars spaced one from the other for supplying high frequency current to the apparatus,

(b) a first induction coil component of conducting ma terial engageable with one of said bus bars and having coolant passages through it,

(c) a second induction coil component of conducting material engageable with the other of said bus bars and also having coolant passages through it,

((1) a third induction co-il component of conducting material engageable with said first and second components to form a single turn induction coil,

(e) means for supplying coolant to the passages of said first and second components,

(f) means for resiliently supporting a part to be heat treated in spaced relation to said first and second components when they are in engagement with bus bars and with said third component,

(g) means for moving said third component and said pair of bus bars into and out of communicating position with respect to said first and second induction coil components,

- (h) means for moving said first and second induction coil components into and out of engagement With said bus bars and said third component when said third component and bars are in said communicating position with respect to said first and second components and into and out of clamping-chilling engagement With said part by compressing said resilient supporting means when said third component and bars are out of said communicating position with respect to said first and second components.

4. An apparatus according to claim 3 wherein said first and second components have flat, relatively large, tapered surfaces formed on ends of them for engagement with flat, relatively large, beveled surfaces on the third component to provide good electrical contact between these components and to accurately locate the first and second components in a predetermined spaced relation one to the other.

5. In a heat treating apparatus,

(a) a pair of bus bars spaced one from the other for supplying high frequency current to the apparatus,

(b) a first induction coil component of conducting material comprising a pair of plates fixed one to the other in conductive relation and having a coolant passage through them, one of said plates being engageable with one of said bus bars,

() a second induction coil component of conducting material comprising a pair of plates fixed one to the other in conductive relation and having a coolant passage through them, one of said plates being engageable with the other of said bus bars,

((1) a third induction coil component of conducting material having a coolant passage through it and engageable with the other plate of said first and second induction coil components to form a single turn induction coil,

(e) means for supplying coolant to the passages in said components,

(f) means for resiliently supporting a part to be heat treated in spaced relation to said other plates of said first and second components when said one plate of said first and second components are in engagement with the bus bars and said third component is in engagement with said other plates,

(g) means for moving said third component and said pair of bus bars into and out of a communicating position with respect to said first and second induction coil components, and

(h) means for moving said one plate of said first and second components into and out of engagement with said bus bars and said third component when said third component and bars are in said communicating position with respect to said first and second components and for moving the other plates of said first and second components into and out of chilling engagement with said part by compressing said resilient supporting means when said third component and bars are out of said communicating position with respect to said first and second components.

6. In a heat treating apparatus for metal parts,

(a) a heating and chilling assemblage comprising a pair of opposed coil halves and a shunt member for cooperation with said halves to form a single turn induction coil,

(b) current supply bus bars for supplying high frequency current to said halves,

(c) means for moving the shunt member into and out of shunting engagement with said coil halves to form said induction coil,

the

(d) means for moving said coil halves into and out of a communicating position with respect to said bus bars,

(e) means for supplying coolant to the interior of said halves,

(f) means for resiliently supporting a part between said halves, and

(g) means for moving said halves into and out of electrical contact with said bus bars when said coil halves are in said communicating position with respect to said bus bars to connect them to the high frequency current and for thereafter moving said halves to compress said resilient supporting means thereby clamping a part between them to chill it when said shunt member and said pair of bus bars are out of communicating position with respect to said coil halves.

7. In a heat treating apparatus for metal parts,

(a) a turntable having an electrically insulated surface and indexable to a plurality of positions,

(b) a plurality of heating and chilling assemblages each comprising a pair of opposed coil halves and a shunt member for cooperation with said halves to form a single turn induction coil, one of each of said halves and said shunt members being supported on said surface,

(c) a pair of current supply bus bars at one of said positions for supplying high frequency current to said halves,

(d) means common to all of said shunt members for moving them into and out of shunting engagement with said coil halves to form said induction coil at said one position,

(e) means for supplying coolant to the interior of said halves,

(f) means for indexing said turntable to bring said one of each of said halves and said shunt member into said one position and to other positions,

(g) means for resiliently supporting a part between and Y in spaced relation with said halves, and

(h) means in each assemblage for moving said halves into electrical contact with said bus bars to connect them to the high frequency current at said one position and for thereafter moving said halves to compress said resilient supporting means thereby clamping a part between them to chill it at other positions when said shunt member is moved out of shunting engagement with said coil halves.

8. An apparatus according to claim 7 wherein the means for supporting the part normally tends to hold the part in spaced relation to the halves and is movable to nest in said one half when the part is clamped between the halves.

9. The method of heat treating metal parts to harden them comprising (a) resiliently supporting a part to be heat treated in spaced relation to a first cooled electrical conducting member,

(b) moving a plurality of other cooled electrical con ducting members into conductive engagement with said first conducting member to form a single turn induction coil, the surfaces of which are in spaced relation to said part,

(c) supplying said single turn coil with current to heat the part to a predetermined temperature,

(d) disengaging one of said conducting members from its companion members forming the coil, and

(e) moving said first member to clamp the part between said first member and one of said plurality of members to chill the part.

70 10. The method of heat treating metal parts to harden them which comprises (a) resiliently supporting a part to be heat treated in spaced relationship to a first electrical conducting member,

(b) moving a plurality of other electrical conducting members into conductive engagement with said first conducting member to form a single turn induction coil, the interfaces of which are maintained in spaced relation to said part,

(c) supplying said coil with high frequency current to heat the part to a predetermined temperature,

(d) disengaging one of said conducting members from its companion members which formed the coil,

(e) continuously supplying said members with a coolant,

(f) moving said first conducting member toward one of the other conducting members to compress said resiliently supported part thereby clamping said part between said first and said one of the other conducting members, and

(g) utilizing said first member and said one of the other conducting members which had formed the coil to simultaneously chill and straighten the part.

References Cited by the Examiner UNITED STATES PATENTS 2,343,889 3/1944 Denneen et a1. 219--10.79 XR 2,565,957 8/1951 Evans. 2,942,089 6/1960 Baker et a1. 21910.69

JOHN F. CAMPBELL, Primary Examiner.

JAMES H. TAYMAN, JR., Examiner.

J. J. MULLEN, Assistant Examiner. 

1. IN A HEAT TREATING APPARATUS, (A) A PAIR OF BUS BARS SPACED ONE FROM THE OTHER FOR SUPPLYING HIGH FREQUENCY CURRENT TO THE APPARATUS, (B) A FIRST INDUCTION COIL COMPONENT OF CONDUCTING MATERIAL ENGAGEABLE WITH ONE OF SAID BUS BARS, (C) A SECOND INDUCTION COIL COMPONENT OF CONDUCTING MATERIAL ENGAGEABLE WITH THE OTHER OF SAID BUS BARS, (D) A SHUNT MEMBER OF CONDUCTING MATERIAL ENGAGEABLE WITH SAID FIRST AND SECOND INDUCTION COIL COMPONENTS TO FORM A SINGLE TURN INDUCTION COIL, (E) MEANS FOR SUPPLYING COOLANT TO THE INTERIOR OF SAID INDUCTION COIL COMPONENTS AND SHUNT MEMBER, (F) MEANS RESILIENTLY MOUNTED ON SAID FIRST INDUCTION COIL COMPONENT FOR SUPPORTING A PART TO BE HEAT TREATED IN SPACED RELATION TO SAID FIRST AND SECOND INDUCTION COIL COMPONENTS WHEN THEY ARE IN ENGAGEMENT WITH THE BUS BARS AND WITH SAID SHUNT MEMBER, (G) MEANS FOR MOVING SAID FIRST AND SECOND INDUCTION COIL COMPONENTS INTO AND OUT OF A COMMUNICATING POSITION WITH RESPECT TO SAID PAIR OF BUS BARS, AND (H) MEANS FOR ACTUATING SAID INDUCTION COIL COMPONENTS WHEN THEY ARE OUT OF SAID COMMUNICATING POSITION WITH RESPECT TO SAID PAIR OF BUS BARS TO COMPRESS SAID RESILIENTLY MOUNTED SUPPORTING MEANS, THEREBY CAUSING INIMATE CLAMPING ENGAGEMENT OF SAID FIRST AND SAID SECOND INDUCTION COIL COMPONENTS WITH SAID PART TO CHILL IT BY CONDUCTION. 